<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        .sky{
            width: 520px;
            font-size: 16px;
            line-height: 14px;
            /*【2】line-height能够设置行内元素的行框高度，这是行内格式化*/
        }
        .sky > span{
            border:1px solid green;
        }
        /*【1】多行文本设置边框，书上说上一行的下边框会在下一行的上边框的下面，即重叠*/
        /*，但是我试验后刚好相反。也许规则改掉了*/

    </style>
</head>
<body>
<div>
    <p class="sky">
        <span>
             this text is written by sky,
        and you can see <br/>
                some word ,and nothing
               this text is written by sky,
        and you can see
                some word ,and nothing
               this text is written by sky,
        and you can see
                some word ,and nothing
        </span>
    </p>
</div>
</body>
</html>